Single-chip common-drain JFET device and its applications

Abstract

A single-chip common-drain JFET device comprises a drain, two gates and two source arranged such that two common-drain JFETs are formed therewith. Due to the two JFETs merged within a single chip, no wire bonding connection is needed therebetween, thereby without parasitic inductance and resistance caused by bonding wire, and therefore improving the performance and reducing the package cost. The single-chip common-drain JFET device may be applied in buck converter, boost converter, inverting converter, switch, and two-step DC-to-DC converter to improve their performance and efficiency. Alternative single-chip common-drain JFET devices are also provided for current sense or proportional current generation.

1. An inverting converter comprising:
 a single-chip common-drain JFET device including:
 a drain coupled to ground; 
 a first gate; 
 a first source coupled to an output, the first source in conjunction with the drain and first gate to form a first JFET; 
 a second gate; and 
 a second source coupled to an input voltage, the second source in conjunction with the drain and second gate to form a second JFET; and 
 
 a controller for providing a first control signal coupled to the first gate and a second control signal coupled to the second gate, to switch the first and second JFETs to convert the input voltage to an output voltage on the output. 
 
   
   
     2. The inverting converter of  claim 1 , further comprising a diode coupled between the first source and drain. 
   
   
     3. The inverting converter of  claim 2 , wherein the diode is integrated with the device in a chip.